Video processing architecture

Abstract

An apparatus and method for displaying portions of either a stationary plane image or a movable plane image on a video display. The image formed being composed of image element character blocks, each character block being represented in an addressable character memory. The character block in said movable plane being movable continuously in an upward/downward motion and in a sideways motion in combination and with a move resolution of one pixel or one line.

I claim: 
     
       1. An apparatus for selectably displaying a stationary plane image and a movable plane image on a video display, comprising: first means for storing image forming instructions at addressable storage locations and for supplying said image forming instructions from each addressable storage location;   a processor coupled to said first means for assembling said stationary plane image and assembling said movable plane image during a display interval, in accordance with said image forming instructions, and in response to image forming data input to said processor via a processor data bus;   a video controller coupled to said processor for generating a vertical display synchronization signal output and a horizontal display synchronization signal output;   a character generator including a plurality of addressable character blocks from which a display image output may be formed;   second means having an input coupled to said processor for storing said assembled stationary plane image and said assembled movable plane image, said second means having an output coupled to said character generator for selecting character blocks within said character generator for display according to said assembled stationary plane image and said assembled movable plane image;   a row subtractor coupled to said processor for discretely shifting said movable plane image in a vertical display axis once during each display interval;   a horizontal counter coupled to said processor for discretely shifting said movable plane image in a horizonal display axis once during each display interval; and   means coupled to said character generator for selecting, according to a processor assigned priority and on a picture element basis, between display of said stationary plane image and display of said movable plane image and for forming a composite image to be displayed.   
     
     
       2. The apparatus of claim 1, further comprising means coupled to said image selecting means for assigning, on a character block basis and under processor control, color attributes to said composite image to be displayed. 
     
     
       3. The apparatus of claim 2, further comprising means coupled to said color assigning means for generating a background plane image associated with said composite image to be displayed. 
     
     
       4. The apparatus of claim 3, further comprising means coupled to said row subtractor and said horizontal counter for reversing said composite image to be displayed. 
     
     
       5. An apparatus for forming a composite video image including a stationary plane image component and a movable plane image component on a video display and in response to externally generated image forming commands, comprising: a first memory for storing image forming instructions at addressable memory locations, said image forming instructions producing a memory output when an associated memory location is addressed;   a central processing unit coupled to said first memory, said processor assembling said stationary plane image component and said movable plane component during a composite video image display interval and in accordance with said image forming instructions from said first memory, said processor being responsive to image forming commands provided at a processor data input bus;   a video controller coupled to said central processing unit for generating a vertical display synchronization signal and for generating a horizontal display synchronization signal;   a stationary plane random access memory for assembling character addresses corresponding to said stationary plane image component in response to data and commands supplied by said processor;   a movable plane random access memory for assembling character addresses corresponding to said movable plane image component in response to data and commands supplied by said processor;   a character generator including a plurality of addressable character blocks from which a display image output may be formed in response to character addresses stored in said stationary and movable random access memories;   a row subtractor coupled to said processor for discretely shifting said movable plane image component position in a vertical display axis once during each display interval;   a horizontal counter coupled to said processor for discretely shifting said movable plane image component position in a horizontal display axis once during each display interval;   means for converting assembled character block image information corresponding to said stationary plane component and corresponding to said movable plane component intp digital video line information;   means for selecting, according to a processor assigned priority and on a picture element basis, between display of said stationary plane image component and said movable plane image component and for forming a composite video image to be displayed; and   a digital-to-analog converter for converting said digital line information to analog video information corresponding to said composite video image.   
     
     
       6. The apparatus of claim 5, further comprising: a color memory for storing a plurality of image colors, said image colors being assignable under processor control on a character block basis; and   means coupled to said processor for selecting colors to be displayed on a character block basis.   
     
     
       7. The apparatus of claim 6, further comprising: means for generating a background plane image component of the composite video image to be displayed; and   a background color select switch for assigning one of a plurality of background colors to said background plane.   
     
     
       8. The apparatus of claim 5, further comprising: means for reversing said composite video image to be displayed including:   (a) a reverse video latch coupled to said row subtractor for reversing the order of display of said video lines; and   (b) a reverse plane control for reversing in mirror image fashion each video line.   
     
     
       9. A method for forming a composite video image during a display interval from a stationary plane image component and from a movable plane image component in response to externally generated image forming commands, comprising the steps of: retrieving, by means of a processor, image forming instructions stored at addressable storage locations in an image forming instruction memory, the image forming instructions being retrieved in response to said image forming commands;   assembling a stationary plane image consisting of a plurality of character block addresses in a stationary plane image memory in accordance with said retrieved image forming instructions;   assembling a movable plane image consisting of a plurality of character block addresses in a movable plane image memory in accordance with said retrieved image forming instructions;   generating a vertical display synchronization signal and a horizontal display synchronization signal;   forming a stationary plane image component from a plurality of character blocks stored in a character generator and in accordance with said character block addresses assembled in said stationary plane image memory;   forming a movable plane image component from a plurality of character blocks stored in a character generator and in accordance with said character block addresses stored in said movable plane image memory;   discretely shifting said movable plane component in a vertical display axis once during each display interval by means of a row subtractor coupled to said processor;   discretely shifting said movable plane component in a horizontal display axis once during each display interval by means of a horizontal counter coupled to said processor; and   selecting, according to a processor assigned priority and on a picture element basis, between display of said stationary plane image component and said movable plane image component to form a composite video image to be displayed.   
     
     
       10. The method of claim 9, further comprising the steps of; selecting a color to accompany each character block from a plurality of colors stored in a color selection memory.   
     
     
       11. The method of claim 10, further comprising the steps of generating a background plane image component of said composite video image.